The oil that is best for frying steak is avocado oil, canola oil, safflower oil or grapeseed oil to achieve a crust on the steak without burning.
Avocado oil is also cited often as the top choice of oil for frying steak for it's stability.
When frying steak you should avoid using extra virgin olive oil, because of it's low smoke point, but you can also use butter for basting the steak at the end, but not for the initial searing of the steak.
When searing steak, you want oils that are neutral flavored with high smoke points.
When it comes to searing steak, avocado oil is considered the king of oils for searing steaks as it has a very high smoke point of around 520 F and a mild flavor.
Grapeseed oil is another great oil for frying steak and is also neutral and great for high heat searing.
Safflower oil has a high smoke point of around 450 F and a neutral taste, which makes it perfect for frying steaks.
Canola oil is a popular cooking oil and neutral and handles the high heat of searing well and can handle heat around up to 425 F and so it's great for frying and searing steaks.
And beef tallow and duck fat are also great options for frying steak as they add flavor and are great for searing with.
The extra virgin olive oil is not good for frying steak as it has a low smoke point of around 320 F, so the extra virgin olive oil is best for finishing the steaks or low heat.
And regular butter will result in the milk solids burning easily, so it's better to use clarified butter for flavor later or ghee or add the butter later for flavor.
For best results when frying steak, use a high smoke point oil like avocado for the initial sear of the steak, then add butter, garlic and herbs like thyme or rosemary to the pan during the last few minutes and then tilt the pan to base the steak for a nice rich flavor.